In recent years, high functionality and miniaturization have been demanded for an optical transceiver used in an optical communication system. For such demands, an optical transceiver including a programmable microcontroller is known. For example, Patent Literature 1 (Japanese Unexamined Patent Publication No. 2014-165780) describes an optical transceiver including a logic device of a monitoring control system that performs communication for monitoring and control by an upper layer (host device) in the OSI (Open Systems Interconnection) reference model, and a CPU (Central Processing Unit) that controls the optical transceiver.
Further, as described in Patent Literature 2 (International Publication No. 2013/012015), an optical transceiver including a digital signal processing circuit configured by a programmable FPGA (Field Programmable Gate Array) is known. The digital signal processing circuit performs digital signal processing of transmission signals (main signals) transmitted or received by an optical transceiver. In this way, an optical transceiver is sometimes made highly functional by including not only a microcontroller but also an FPGA in a path (main signal system) that transmits main signals.